ML20081B475

Twelfth Interim Deficiency Rept Re Main Steam Line Failure Due to Main Feedwater Overfill.Initially Reported on 800319. Field Change Package Submitted by B&W.Next Rept by 840622. Also Reportable Per Part 21

ML20081B475
Person / Time
Site:	Bellefonte
Issue date:	02/27/1984
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-84 NUDOCS 8403090181
Download: ML20081B475 (3)

Text

( ;; _41. q.'

TENNESSEE VALLEY AUTHORITY r

l' rH ATTANOOG A, TENNESSEE 37401 400 Chestnut Street Tower II

• 2 NO : 5 5 February 27, 1984 U.S. Nuclear Regulatory Commission Region II Attn:- W. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

BELL 3FONTE NUCLEAR PLANT UNITS 1 AND 2 - FAILURE OF MAIN STEAM LINES

. BECAUSE OF MAIN FEEDWATER OVERFILL - NCR BLN NEB 8004 - TWELFTH

. INTERIM REPORT On March 19, 1980, Bruce Cochran, NRC-0IE Region II, was informed that the subject nonconformance was determined to be reportable in accordance

.with 10 CFR 50.55(e). This was followed by our interim reports dated

-April 17, September 23, and December 29,1980; June 25 and December 28, 1981; March 31, Augu't 27, and November 18, 1982; and March 24, July 14, and November 18, 198;, Enclosed is our twelfth interim report. We expect to submit our next report by June 22, 1984. We consider 10 CFR Part 21 to be applicable to this nonconformance'.

If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2474.

Very truly yours, TENNESSEE VALLEY AUTHORITY L.

M'. Mills, Marager Nuclear Licensing

' Enclosure oc (Enclosure):

. Mr. Richard C. DeYoung, Director

.0ffice of Inspection and Enforcement

.U.S. Nuclear' Regulatory Commission Washington, D.C.

20555 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Saite 1500 Atlanta, Georgia 30339 Babcock & Wilcox Company-P.O. Box 1260-

~

Lynchburg,' Virginia 24505 Attention:.Mr. H. B. Barkley S403090181 840227 PDR ADOCK 05000438 OFFICIAL COPY S

PDR

,_l&T d

1983-TVA SOTH ANNIVERSARY

\\

^"""""*"1"'"*"

)l

~

m p )c

,,5 K. -

-ENCLOSURE

~

BELLEFONTE NUCLEAR PLANT UNITS-1 AND 2 FAILURE OF MAIN STEAM LINES BECAUSE OF MAIN FEEDWATER OVERFILL 1

NCR BLN NEB 8004 10 CFR 50.55(e)

TWELFTH INTERIM REPORT Description of Deficiency A preliminary safety concern, PSC 35-79, was initiated within B&W, Lynchburg, Virginia,.which presents the concern that a potential exists for overfilling steam generators by excessive addition of main feedwater (MFW) or auxiliary feedwater (AFW).

Excessive feedwater addition, as used here, is defined as a condition which

+

would exist if feedwater (main or auxiliary) is continually added to the steam generators 'in an unplanned fashion at a rate greater than the core heat generation capability for converting it to steam. Overfill, the condition addressed in this preliminary safety concern, may be defined as a limiting case of excessive feedwater addition which allows liquid spillage

~ into'the steam lines.

c

'I't is estimated that the time to overfill' the integral economizer once-through ' steam generators (IEOTSG) provided on the Bellefonte Nuclear' Plant is approximately 2 to 4 minutea with MFW and between 7 to 15 minutes with AFW.

Potential results of overfill could be:

1. -Steam line deformation and: failure because of water accumulation.

2.

Steam generator' blowdown because of steam line failure with the

. potential for core return tt power from a safe shutdown condition, excessive' steam generator' tube stress, exceeding reactor vessel NDT limits, 'or containment overpressurization.

-Interim Progress

= The' corrective action for this NCR undertaken by B&W was to provide a

. design for a safety grade MFW and AFW overfill protection system for the steam generators. B&W has proceeded to provide such a MFW

. overfill protection system via the BLN upgrade "do it now" (DIN) program item 702..This program is-the TVA-instituted program to amet

. post-Three Mile Island (TMI) upgrade requirements. However, it has

'been determined that an AFW overfill protection system is not required; thus, this action is not being pursued. B&W has submitted to TVA a field change package (FCP).for implementation of DIN 702;

- however, this FCP.has.not been approved and is currently undergoing a substantial design change by B&W. The percent completion of this

' corrective action is less than 25 percent.

s 5l W

4

?

y2 i

?

x x w mu y

,'W

- ____ = ____=__

+ - -

(.

e

. q..

TVA is still in the process of reviewing and approving the analysis whi';h shows that the main steam line piping can withstand the MFW overfill event, and thus, no failure problem would exist. The preliminary analysis appears to be acceptable, and TVA's Nuclear Engineering Support Branch (NEB) is awaiting verification and approval of the final analysis by the Civil Engineering Support Branch (CEB).

CEB has completed the verification and approval of fcur of six analysis problems associated with this item.

(Problems N4-1(2)SM-K,L,M,N, have been completed; problems N4-1(2)SM-A,C are not yet

' finished). A copy of the completed, verified, and approved analysis will be sent to B&W for their information and review.

4 t4-4 e

k

%4

=jy

.,,.7

-mi g

g P M +

_t N

y

. s g, 5

,q._ &" ' c ;; a g g s,,

,,? yJ '_+1,p J

,y'

- #4%.A..,